<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="author
    " content="只会切图的前端">
    <title>五星红旗</title>
</head>
<body>
    <div class="box">
        <div class="star"></div>
        <div class="small-star one"></div>
        <div class="small-star two"></div>
        <div class="small-star three"></div>
        <div class="small-star four"></div>

    </div>
    <style>
        .box{
            width: 300px;
            height: 200px;
            margin-top: 60px;
            background: red;
            position: relative;
        }
        .star{
            margin-top: 40.73px;
            margin-left: 21.47px;
            width: 0;
            height: 0;
            border-top: 20.73px solid yellow;
            border-left: 28.53px solid transparent;
            border-right: 28.53px solid transparent;
            position: absolute;
        }
        
        
        .star:before{
            content: "";
            display: block;
            width: 0;
            height: 0;
            position: absolute;
            border-top: 20.73px solid yellow;
            border-left: 28.53px solid  transparent;
            border-right: 28.53px solid transparent;
            transform: rotate(72deg);
            top: -20.73px;
            left: -28.53px;
            transform-origin: 28.53px 9.27px;
        }
        .star:after{
            content: "";
            display: block;
            width: 0;
            height: 0;
            position: absolute;
            border-top: 20.73px solid yellow;
            border-left: 28.53px solid  transparent;
            border-right: 28.53px solid transparent;
            transform: rotate(-72deg);
            top: -20.73px;
            left: -28.53px;
            transform-origin: 28.53px 9.27px;
        }

        .small-star{
        
        
            width: 0;
            height: 0;
            position: absolute;
            border-top: 6.91px solid yellow;
            border-left: 9.51px solid  transparent;
            border-right: 9.51px solid transparent;
            transform-origin: 9.51px 3.09px;
        }
        .small-star:before{
            position: absolute;
            width: 0px;
            height: 0px;
            content: "";
            display: block;
            border-top: 6.91px solid yellow;
            border-left: 9.51px solid transparent;
            border-right: 9.51px solid transparent;
            transform: rotate(-72deg);
            top: -6.91px;
            left: -9.51px;
            transform-origin: 9.51px 3.09px;

        }
        .small-star:after{
            position: absolute;
            width: 0px;
            height: 0px;
            content: "";
            display: block;
            border-top: 6.91px solid yellow;
            border-left: 9.51px solid transparent;
            border-right: 9.51px solid transparent;
            transform: rotate(72deg);
            top: -6.91px;
            left: -9.51px;
            transform-origin: 9.51px 3.09px;

        }
        .one{
            top: 16.91px;
            left: 90.49px;
            transform: rotate(-48.96deg);
        }
        .two{
            top: 36.91px;
            left: 110.49px;
            transform: rotate(-26.13deg);
        }
        .three{
            top: 66.91px;
            left: 110.49px;
            transform: rotate(-2.06deg);
        }
        .four{
            top: 86.91px;
            left: 90.49px;
            transform: rotate(-20.66deg);
        }
    </style>
</body>
</html>